Clean-up of small ferro-metallic items at a construction site, playground, or similar location can be very difficult to carry out in a cost- and time-effective manner. In the construction industry, providing a clean and safe environment, both during the building phase and upon completion, is very important. Screws and nails, which are often discarded throughout the day by employees, can be very dangerous. This danger poses a problem to vehicles as well as to people on the jobsite. These items, if not immediately picked up, may become lodged in the ground over time, especially if the soil has become dampened, as from rain, causing the soil to compact and harden. Ferro-metallic items also remain buried in ground coverings, such as gravel and taller grass, and magnetic force alone will often not disentangle and remove these items.
One current type of tool that is used for this purpose is a hand-held magnetic wand or other implement that can be waved or lightly dragged over the ground to attract ferro-metallic items off the surface. These types of devices cannot agitate the soil or other ground cover to consistently and sufficiently pick up the dangerous ferro-metallic items that may be embedded in the ground cover.
Another type of current device used to pick up ferro-metallic items is a large rolling magnetic sweeper, which cannot maneuver well around shrubbery. Such rolling sweepers may be a viable option when sweeping larger, hard, smooth surfaces of ferro-metallic items, but they are unable to get in around shrubbery and other tight areas to retrieve the ferro-metallic items. Furthermore, rolling sweeper devices sweep over the ground surface without digging into the ground surface, thus potentially missing debris that is wholly or partially buried in the ground. Adding lightweight tines to the sweeper, such as the flexible tines of the types commonly used for a leaf rake, does not provide the device with strength to unearth nails or other debris that has become embedded in compacted soil or buried amongst taller grass or gravel.
As ferro-metallic items become buried in the ground, it is sometimes customary to first mechanically agitate the ground with a conventional rake, and then to follow up with a magnetic pick-up device, making the job a two-step process, and requiring two different tools, in order to do an effective job.
Furthermore, the surface of a magnetic pick-up device may become loaded during use with the ferro-metallic debris that has been attracted to it, making the device very heavy to maneuver and reducing its effectiveness. Lifting the heavily loaded device and knocking off the debris or taking steps to reduce a magnetic field associated with the device may rid the device of the heaviest of the debris, but may not successfully release all of the debris, especially lighter-weight debris, such as staples and metallic filings, that remain more readily attracted to a magnetic field of lesser strength.
Magnetic devices that do not provide a shut-off or magnet-release mechanism, or that do not allow a user to comfortably keep the rake in a non-magnetized state, suffer from the limitation that the rake is always used as a magnetic rake, without an option for use as a conventional, non-magnetized rake.